In this paper we attempt to formulate logical foundations for a theory of actions or performance. Human beings act in various ways, and their actions are intimately interrelated with their use of language. But precisely how actions and the use of language are interrelated is not very clear. One of the reasons is perhaps that we have no precise vocabulary in terms of which such interrelations may be handled. There is need for developing a systematic theory in which different kinds of actions may be discussed, contrasted, and compared. Then the various interrelations between actions and linguistic usage may perhaps be discussed rather more carefully and thoroughly than heretofore. Although much important preliminary work has been done in the analysis of actions, no one it seems has attempted to develop a strict logical theory for such analysis. A few tentative and programmatic steps were taken in the author's Toward a Systematic Pragmatics. Let us attempt here to improve those and take a few more. Any first attempts of this kind are of course fraught with difficulties. There inevitably will be some oversimplification or some overelaboration here or there. Ultimately of course we are interested in interrelating performance with various notions from syntax, semantics, and quantitative pragmatics. But this is not easy and only a few tentative suggestions toward such a development can be given here. In section 1 the distinction between action-kinds and action-events is drawn, and the character of the primitive or primitives needed for the theory of performance is discussed. In section 2 some further notions are then defined. Certain Rules of Performance are suggested in section 3. In section 4 there is discussion of the somewhat tenuous notion of acceptance as a basis for action. In section 5 the fundamental notions required for Parsons and Shils' theory of social action is discussed briefly. In section 6 we attempt to define the two basic notions required in Leonard's recent papers concerning authorship and purpose. Finally, in section 7, the theory of performance is interrelated with von Wright's deontic logic, in which such notions as permission and obligation are considered